textproduct: Quad Cities

KEY MESSAGES

- Heat and humidity will return around mid-week with temperatures in the 90s and heat indices pushing 100 or higher. The probability of heat headlines around mid-week is 33-40 percent.

- Severe storms are possible Tuesday night through Thursday night. Widespread severe thunderstorms are possible on Wednesday and Thursday.

SHORT TERM /THROUGH TUESDAY NIGHT/

Issued at 313 PM CDT Mon Jun 8 2026

Negatively tilted 500 MB trough is forecast to continue to lift northeastward into the the Lower Great Lakes this evening. Winds are forecast to become light and variable and given abundant low level moisture and recent heavy rains across the area, low clouds and fog are forecast to develop across the area tonight with more widespread fog possible along and north of Highway 30.

Models show a weak shortwave moving eastward across the region tonight into Tuesday morning. There are big differences in the placement of this shortwave with some models moving the shortwave across northern Missouri while others move it across northern Iowa. Model consensus keeps the POPs to the south of the area and decided to leave chances of precipitation out of the forecast due to low confidence in this occurring.

It will be hot and humid across the area on Tuesday if morning convection remains out of the area. High temperatures on Tuesday will be around 90 degrees across the area and with dew points in the lower to mid 70s head indices will be in the upper 90s with an hour or two with heat indices around 100 degrees.

Given the instability, any storms that develop during the day will have the potential for damaging winds. Models continue to show the low level jet developing after 00 UTC Wednesday as a warm front lifts across the area and this may result in more showers and storms developing across the area north of Highway 30. The main threats with these storms will be from damaging winds. The Storm Prediction Center has a Marginal (level 1 out of 5) Risk for severe thunderstorms Tuesday night.

LONG TERM /WEDNESDAY THROUGH MONDAY/

Issued at 313 PM CDT Mon Jun 8 2026

An unusually strong and deep 500 MB trough is forecast to move into the Northern Plains and Upper Midwest Wednesday through Thursday with two shortwaves moving through the base of the trough and across the area. A warm and unstable airmass is forecast to be in place across the area on Wednesday. High temperatures will be in the lower to mid 90s Wednesday with dewpoints in the lower to mid 70s. This will yield CAPE values of 3500 to 4500 J/KG and 0 to 6 km shear of 30 to 40 knots. For this reason the storm prediction center has a Enhanced (Level 3 out of 5) Risk of severe thunderstorms with all modes of severe weather possible. These storms will also have the potential for heavy rainfall with precipitable water values returning to around 2 inches. Storms are expected to build into the area from the north Wednesday afternoon into Wednesday evening.

Another shortwave is forecast to move into the base of the trough and eject into the Upper Midwest during the day on Thursday. This will drive a cool front across the area during the day. There appears to be a coupled jet streak as the area sits between the right entrance of a departing jet streak and the right exit region of a jet streak lifting into the area. Models again show the potential for 3500 to 4500 J/KG of CAPE with 20 to 30 knots of deep layer. Storms are expected to develop across the area with potential for supercells with all modes of severe weather possible. The Storm Prediction Center also has the area highlighted with a 30 percent chance of severe thunderstorms on Thursday.

The region will remain under broad cyclonic flow through early next week with the potential for fast moving shortwaves to move across the area through the weekend into early next week. This will result in periods of showers and thunderstorms across the area through the reminder of the period.

AVIATION /00Z TAFS THROUGH 00Z WEDNESDAY/

Issued at 705 PM CDT Mon Jun 8 2026

Isolated showers are possible through early tonight mainly at DBQ with dry conditions expected late and into Tuesday AM. Moist low-level conditions combined with light winds may result in areas of fog late tonight into early Tuesday AM, but with low confidence on extent and severity. DBQ has the greatest potential for a period of low stratus and fog which could become briefly dense (IFR/LIFR). Elsewhere, if fog forms it may be more of the patchy and shallow variety. MVFR ceilings may linger trough Tuesday AM at DBQ, with VFR anticipated to the south.

DVN WATCHES/WARNINGS/ADVISORIES

IA...None. IL...None. MO...None.